Use interior mutability for StableHashingContext::caching_source_map.

compiler/rustc_abi/src/extern_abi.rs

@@ -217,9 +217,9 @@ impl Hash for ExternAbi {
 }
 
 #[cfg(feature = "nightly")]
-impl<C> HashStable<C> for ExternAbi {
+impl<Hcx> HashStable<Hcx> for ExternAbi {
     #[inline]
-    fn hash_stable(&self, _: &mut C, hasher: &mut StableHasher) {
+    fn hash_stable(&self, _: &Hcx, hasher: &mut StableHasher) {
         Hash::hash(self, hasher);
     }
 }

compiler/rustc_ast/src/ast.rs

@@ -121,7 +121,7 @@ impl PartialEq<&[Symbol]> for Path {
 }
 
 impl<Hcx: rustc_span::HashStableContext> HashStable<Hcx> for Path {
-    fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
+    fn hash_stable(&self, hcx: &Hcx, hasher: &mut StableHasher) {
         self.segments.len().hash_stable(hcx, hasher);
         for segment in &self.segments {
             segment.ident.hash_stable(hcx, hasher);

compiler/rustc_ast/src/tokenstream.rs

@@ -139,7 +139,7 @@ impl<D: SpanDecoder> Decodable<D> for LazyAttrTokenStream {
 }
 
 impl<Hcx> HashStable<Hcx> for LazyAttrTokenStream {
-    fn hash_stable(&self, _hcx: &mut Hcx, _hasher: &mut StableHasher) {
+    fn hash_stable(&self, _hcx: &Hcx, _hasher: &mut StableHasher) {
         panic!("Attempted to compute stable hash for LazyAttrTokenStream");
     }
 }
@@ -828,7 +828,7 @@ impl<Hcx> HashStable<Hcx> for TokenStream
 where
     Hcx: crate::HashStableContext,
 {
-    fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
+    fn hash_stable(&self, hcx: &Hcx, hasher: &mut StableHasher) {
         for sub_tt in self.iter() {
             sub_tt.hash_stable(hcx, hasher);
         }

compiler/rustc_ast_lowering/src/lib.rs

@@ -602,9 +602,9 @@ fn compute_hir_hash(
         .collect();
     hir_body_nodes.sort_unstable_by_key(|bn| bn.0);
 
-    tcx.with_stable_hashing_context(|mut hcx| {
+    tcx.with_stable_hashing_context(|hcx| {
         let mut stable_hasher = StableHasher::new();
-        hir_body_nodes.hash_stable(&mut hcx, &mut stable_hasher);
+        hir_body_nodes.hash_stable(&hcx, &mut stable_hasher);
         stable_hasher.finish()
     })
 }

compiler/rustc_codegen_cranelift/src/driver/aot.rs

@@ -46,7 +46,7 @@ enum OngoingModuleCodegen {
 }
 
 impl<Hcx> HashStable<Hcx> for OngoingModuleCodegen {
-    fn hash_stable(&self, _: &mut Hcx, _: &mut StableHasher) {
+    fn hash_stable(&self, _: &Hcx, _: &mut StableHasher) {
         // do nothing
     }
 }

compiler/rustc_codegen_llvm/src/common.rs

@@ -302,9 +302,9 @@ impl<'ll, 'tcx> ConstCodegenMethods for CodegenCx<'ll, 'tcx> {
                             };
                             if !self.sess().fewer_names() && llvm::get_value_name(value).is_empty()
                             {
-                                let hash = self.tcx.with_stable_hashing_context(|mut hcx| {
+                                let hash = self.tcx.with_stable_hashing_context(|hcx| {
                                     let mut hasher = StableHasher::new();
-                                    alloc.hash_stable(&mut hcx, &mut hasher);
+                                    alloc.hash_stable(&hcx, &mut hasher);
                                     hasher.finish::<Hash128>()
                                 });
                                 llvm::set_value_name(

compiler/rustc_codegen_ssa/src/common.rs

@@ -103,7 +103,7 @@ mod temp_stable_hash_impls {
     use crate::ModuleCodegen;
 
     impl<Hcx, M> HashStable<Hcx> for ModuleCodegen<M> {
-        fn hash_stable(&self, _: &mut Hcx, _: &mut StableHasher) {
+        fn hash_stable(&self, _: &Hcx, _: &mut StableHasher) {
             // do nothing
         }
     }

compiler/rustc_data_structures/src/intern.rs

@@ -107,7 +107,7 @@ impl<T, Hcx> HashStable<Hcx> for Interned<'_, T>
 where
     T: HashStable<Hcx>,
 {
-    fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
+    fn hash_stable(&self, hcx: &Hcx, hasher: &mut StableHasher) {
         self.0.hash_stable(hcx, hasher);
     }
 }

compiler/rustc_data_structures/src/packed.rs

@@ -62,7 +62,7 @@ impl fmt::UpperHex for Pu128 {
 
 impl<Hcx> HashStable<Hcx> for Pu128 {
     #[inline]
-    fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
+    fn hash_stable(&self, hcx: &Hcx, hasher: &mut StableHasher) {
         { self.0 }.hash_stable(hcx, hasher)
     }
 }

compiler/rustc_data_structures/src/sorted_map.rs

@@ -349,7 +349,7 @@ impl<K: Ord, V> FromIterator<(K, V)> for SortedMap<K, V> {
 
 impl<K: HashStable<Hcx> + StableOrd, V: HashStable<Hcx>, Hcx> HashStable<Hcx> for SortedMap<K, V> {
     #[inline]
-    fn hash_stable(&self, hcx: &mut Hcx, hasher: &mut StableHasher) {
+    fn hash_stable(&self, hcx: &Hcx, hasher: &mut StableHasher) {
         self.data.hash_stable(hcx, hasher);
     }
 }